My error has gone away after a while. Perhaps one of the people I'm following is using an animated image for their avatar, and they haven't posted anything recently. If so, I assume it'll come back before too long. Is there any way to track down what's triggering this error, i.e. where the image in question is coming from?

It's just happened again. By switching to another client, I'm able to deduce that the next tweet in the stream would have been http://twitter.com/#!/maxogden/status/77668660868677632 which contains a link to an animated GIF. Perhaps, it's trying to display that image inline and choking on it? But why would this be passed to dbusmenu anyway?

The dbusmenu error itself seems harmless; update_icon() should just do nothing. So maybe there is actually a separate Gwibber bug here?